UCE phylogeography of a Neotropical water scavenger beetle reveals deep patterns of interconnectivity among Amazonian savannas

In the fields of Neotropical biogeography and phylogeography, most arthropod research has focused on tropical-forest dwelling taxa, with fewer studies being devoted to tropical savanna species. In the Neotropical hydrophilid genus Chasmogenus, nearly all species occupy aquatic habitats within tropical forests. One lineage, however, has been documented exclusively from savanna and open wetland ecosystems. This lineage has historically comprised two species: Chasmogenus australis and Chasmogenus sapucay. The morphology of these two species is virtually indistinguishable, which presents the question of whether this lineage encompasses one or two species. Here, we use a tailored taxon-specific UCE probe set targeting thousands of loci to capture data from 37 samples distributed from Guatemala down to northern Argentina. Captured UCE datasets are subjected to different combinations of data assembly and processing methods for population-level phylogenetic reconstructions. Results show relatively little genetic structuring across this lineage’s large distribution, indicating substantial interconnectivity between populations that has likely been necessitated by the ephemeral nature of savanna ecosystems.